LABRADAR PROS AND CONS

[Dusty Stevens]

I see. So youre saying that because it tracks and transmits readings at different distances, it doesnt necessarily need to pick it up right away at the first point because it can judge speed at the rest of the intervals out to 100 yards...?

Yes the trigger only tells it to get ready to watch

 

[Bill Norris]

Its best to use the shortest mini usb cable you can find and velcro the power supply to the side of the unit. Mine came with this even the velcro

Thanks Bro. Got it ordered.

 

[MikeMcCasland]

Has anyone measured the difference in speed when the Labradar is triggered with muzzle report vs. rifle recoil from an inertia trigger?

Watching high speed cameras of rifles being fired, theres no doubt that the bullet and powder blast exits the muzzle well before the rifle ever begins to recoil.

I've now run mine twice off the inertia trigger while I had an MS V3 attached.

First time I did it was when the LR was new to 'check it's accuracy'. It was within ~5 FPS. In the initial testing, I was convinced it was dead on.

Second time I did it was a month or two after owning it. I was getting numbers with the LR that I didn't believe... 30-50fps velocity swings in minor temp changes using H4350. I put the MS V3 on it and shot a string, and the shots were within ~1-5FPS for all 20 of them.

So far as I'm concerned, the LR is accurate with the inertia trigger.

On a related note, you see some interesting things chronographing every round. Changed the way I viewed certain powders/primers/bullets.

 

[Ledd Slinger]

...30-50fps velocity swings in minor temp changes using H4350.
.....
On a related note, you see some interesting things chronographing every round. Changed the way I viewed certain powders/primers/bullets.

If you want to go deeper down the rabbit hole...
There has been some discussions about certain powders that are normally considered temp stable in most cartridges now exhibiting temperature sensitivity in certain case designs. It would seem that in some instances, case dimensions "might" change the characteristics of a powder with how it reacts to temp changes.

However, I am uncertain if there were other atmospheric conditions other than temperature taking effect. H3450 is normally considered a temp stable powder. I am curious which cartridge you experienced this with and whether or not all other atmospheric conditions were the same besides the slight temp difference? Humidity, barometric pressure, etc... Maybe the position of the moon and its level of gravitational pull on the earth? Lol.

But seriously, I am curious because I have also experienced some crazy speed changes in slight temp swings with powders that did not exhibit the same characteristic in other cartridges/rifles.

 

[SGK]

If it chews through a battery very quickly what size external battery packs do people think is needed?

 

[Dusty Stevens]

My 10,000ah lasts for weeks

 

[Ccrider]

Yep. I use a micro start 10. Also good for jumping your car or truck off in a pinch.

 

[nmkid]

Well, mine came in yesterday. The P.O. delivered on a holiday! So, what are most folks doing for a sighting piece(?) Just using the notch on the unit?

 

[SGK]

@powderbrake where did you get the eye protector bit? Very sensible.

 

[Dusty Stevens]

Well, mine came in yesterday. The P.O. delivered on a holiday! So, what are most folks doing for a sighting piece(?) Just using the notch on the unit?

1/4” tubing laid in the notch

 

[nmkid]

1/4” tubing laid in the notch

Lowe's tomorrow morning.

 

[PatMiles]

If it chews through a battery very quickly what size external battery packs do people think is needed?

https://www.amazon.com/gp/product/B00M6VA7OU/?tag=accuratescom-20

 

[arkcomatt]

Well, mine came in yesterday. The P.O. delivered on a holiday! So, what are most folks doing for a sighting piece(?) Just using the notch on the unit?

I bought one from mkmachining.com. Works great and Lr will still fit in the carry case with an arkcomachine.com base.
Couldn't help it. My base and their sight work. Great combination.

 

[nmkid]

I bought one from mkmachining.com. Works great and Lr will still fit in the carry case with an arkcomachine.com base.
Couldn't help it. My base and their sight work. Great combination.

Thanks. Just ordered one.

 

[nmkid]

https://www.amazon.com/gp/product/B00M6VA7OU/?tag=accuratescom-20

View attachment 1137919

So, knowing nothing about these chargers...Do you just buy the one that provides the highest mAh?

 

[PatMiles]

So, knowing nothing about these chargers...Do you just buy the one that provides the highest mAh?

You can probably go about as big as you want but then you'll end up with a Die Hard from Sears.
The 20,000mAh battery will last you a loooong time before you have to charge it. No worries about arriving at the range and finding that the batteries in your LR are tango uniform and your load development is not gonna happen.
You won't be sorry.

 

[powderbrake]

@powderbrake where did you get the eye protector bit? Very sensible.

It was a piece of rubber that I had laying around. I had to put a few wraps of electrical tape to match the hole in the rubber, and I glued it on.

 

[SGK]

And how do you measure any chronographs accuracy?

I was thinking the same thing. You could certainly just accept the accuracy value given by the manufacturer.

I never responded to this. I was hoping to get a response from LabRadar before doing so.

The manufacturer claims it "has an accuracy of 0.1%" (From their FAQ.) However they don't explain what this number is, what statistic it represents, let alone the test conditions under which it was determined. Does it mean that every shot's recorded speed will be accurate to within +/- 0.1%? Think of that as the ES of error. That would be great assuming a high enough number of samples in their test to provide great confidence (interval), none of which we know. Is 0.1% the standard deviation of error? An error SD of 3 fps, versus an average of 3000 fps, would be relatively average even with a high sample count. Or is it another statistic called "Standard Error"?

Standard Error is used to describe the mean of a sample set. That's a very different statistic from the random error of the measurement device. Focused on SD in your load development etc? That's the random variance of your load and the random error of your measurement device combined (on a RMS basis). The latter is not Standard Error.

https://www.radford.edu/~biol-web/stats/standarderrorcalc.pdf

(You can derive SD from Standard Error if you know the number of samples. SD = SE x SQRT(N). If a sample size of 25 (quite low) produced a Standard Error of 3 fps vs an average of 3000 fps then the SD is a whopping 15 fps. That would be p*ss poor.)

So basically the problem is that without more information we have little idea about how 'accurate' or 'precise' the device is. The average velocity of a bunch of shots has only limited value, even if it is accurate. (Most people only think of this average when thinking about device accuracy.) If you look for velocity flat spots in group ladder tests (shot in the same session/setup) it's helpful. The absolute figure provides a starting guide for extrapolating trajectory/drop at further distances, but you'd want to confirm these on paper anyway. It doesn't help at all if you are focused on variance. Here you'd like to know that the measurement device is very precise (has low measurement error) and care less about the absolute number.

Maybe someone got more information from LabRadar or other sources.

 

[Ned Ludd]

Regardless of the precision/accuracy of any chronograph made, the small sample numbers (n) we use for typical load development usually mean that there is not a whole lot of statistical weight behind the findings. Most of the chronographs I've ever used listed the accuracy of measurement to a percent value. Whether correct or not, I believe most of them simply mean "MV =/- some percent of MV when they use that terminology, because an SD or SE value would not normally be expressed as a percentage. FWIW - the LabRadar value of 0.1% among the lower values among manufacturers that actually provide such information. Given other variables that go into the equation such as properly setting up/aiming any chronograph device, the typically small shot sample number (n), etc., I think there is a limit to what we can and can't say from most typical chronograph data. Nonetheless, shooters use chronographs because they work, and they allow for load analysis in a way that is better than it would be without them.

 

[SGK]

Regardless of the precision/accuracy of any chronograph made, the small sample numbers (n) we use for typical load development usually mean that there is not a whole lot of statistical weight behind the findings.

Agreed on this part. And not many understand confidence intervals and just how they're affected by N, and hence how little (statistical) confidence they can have in 3-5 shot strings.

I've been chewing on getting a LabRadar for awhile now. I just hate it when a manufacturer tosses out a technical specification that is utterly meaningless. Currently I use the Two Box Chrono. I have confidence in its inherent precision (very low random error SD) because I've studied the dataset Adam put up on his website. It's accuracy (how well it measures absolute velocity) is very setup-dependent (likely much more so than LabRadar); so much so that I simply don't fuss with setup and rely on it for SD only. It has a few other constraints (forward of firing point, picks up a LOT of other shots on a busy range etc) but these are generally manageable plus it's damn cheap. It does what it was designed for extremely well. I rely on my Shotmarker for average velocity (and back calc muzzle velocity). That said I like toys and it would be nice to see the LabRadar provide both good precision and accuracy.

I called LabRadar and asked them the question about their accuracy statement. I didn't expect the guy who answered the phone to know the answer but sure hope he goes and gets it. Politely he took down my email address and said he would respond. I hope he does. We shall see.